Oscillatory Behavior in Cobalt Electrodeposition with 3-Mercapto-1-Propanesulfonate

Abstract

A potential oscillation was observed during galvanostatic deposition of Co in the presence of 3-mercapto-1-propanesulfonate (MPS) and a systematic study was conducted. A suppression effect on Co deposition by MPS was seen in cyclic voltammetry (CV) and such effect was not affected by pH. To fully understand the suppression effect and oscillation mechanism, several influencing factors in the galvanostatic process such as pH, Co2+ and MPS concentrations, agitation, and a buffer agent were thoroughly investigated. Moreover, mercaptopropionic acid, an alternative additive with a similar molecular structure as MPS, was used to determine the roles of thiol and sulfonate groups during the oscillation. Based on the experiment results, a kinetically controlled mechanism including a potential-dependent adsorption–desorption of the Co–MPS complex accompanied by the accumulation and dissolution of Co­(OH)2 was proposed.

Insights into Chemical Changes Causing Transient Potential Patterns during Cobalt Electrodeposition: An Operando SHINERS Investigation

“…Surprisingly, we observed two distinct oscillations, one within 100 s (denoted as “nucleation oscillation”) and another after 1300 s (denoted as “growth oscillation”) of deposition for the given bath composition. Typically, the first oscillation was at a frequency of 0.1 Hz that was gradually diminishing and eventually disappeared (inset of Figure a) as reported for a similar system . The second oscillation was at a lower frequency (0.02–0.03 Hz) with a considerably higher amplitude.…”

“…7,8 Although electrodeposition is a simple method for Co thin film deposition, often anomalous transient potential oscillatory patterns were observed in the presence and absence of organic additives. 9−13 Similar oscillations have been observed in Cu 12,14,15 and Co 10,16 electrodeposition. Butynediol (2butyne-1,4-diol) is a widely used class II brightener in metal and alloy electrodeposition.…”

“…Metallic cobalt (Co) films have attracted much interest among various experts, particularly in integrated circuit designers due to a shorter electron mean free path (λ rt = 7.77 nm), , which is considered as a promising alternate to copper (Cu) (λ rt = 39.9 nm) in nanoelectronic circuits. , Although electrodeposition is a simple method for Co thin film deposition, often anomalous transient potential oscillatory patterns were observed in the presence and absence of organic additives. − Similar oscillations have been observed in Cu ,, and Co , electrodeposition. Butynediol (2-butyne-1,4-diol) is a widely used class II brightener in metal and alloy electrodeposition. − We have also observed a facilitated hydrogen adsorption and evolution along with Co 2+ reduction at low overpotentials in the presence of butynediol, which leads to the potential oscillations …”

“…Typically, the first oscillation was at a frequency of 0.1 Hz that was gradually diminishing and eventually disappeared (inset of Figure 3a) as reported for a similar system. 10 The second oscillation was at a lower frequency (0.02−0.03 Hz) with a considerably higher amplitude.…”

Potential Oscillations During Cobalt–Nickel Electrodeposition in the Presence of Butynediol

“…15,16 Widely studied oscillatory systems involve (electro-)chemical processes coupled with the diffusion of the solution species to the interface, e.g., oscillatory systems involving adsorption/desorption of metal−ligand complexes and the dissolution of the passive hydroxide layer. 17 We recently reported a new type of oscillatory system during the electrodeposition of cobalt involving adsorbed hydrogen and its chemical scavenging by hydrogenation of organic additives and the dissolution of passive cobalt hydroxide layers under diffusion control. 18 Hydrogenation of butynediol (BD) is an industrially important process where Raney Ni or Co has been used as a heterogeneous catalyst.…”